WO2013084839A1 - Dispositif de capture d'image, appareil électronique, scanner de détection de luminescence stimulée de manière optique et procédé de capture d'image - Google Patents

Dispositif de capture d'image, appareil électronique, scanner de détection de luminescence stimulée de manière optique et procédé de capture d'image Download PDF

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Publication number
WO2013084839A1
WO2013084839A1 PCT/JP2012/081257 JP2012081257W WO2013084839A1 WO 2013084839 A1 WO2013084839 A1 WO 2013084839A1 JP 2012081257 W JP2012081257 W JP 2012081257W WO 2013084839 A1 WO2013084839 A1 WO 2013084839A1
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Prior art keywords
light
pixels
photons
pixel
incident
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PCT/JP2012/081257
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English (en)
Japanese (ja)
Inventor
西原　利幸
角　博文
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ソニー株式会社
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Priority to EP12854949.0A priority Critical patent/EP2790400A1/fr
Priority to CN201280059247.XA priority patent/CN103975580B/zh
Priority to US14/362,313 priority patent/US9462190B2/en
Publication of WO2013084839A1 publication Critical patent/WO2013084839A1/fr
Priority to US15/249,654 priority patent/US10063784B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • H04N23/71—Circuitry for evaluating the brightness variation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/30—Transforming light or analogous information into electric information
    • H04N5/32—Transforming X-rays
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64—Fluorescence; Phosphorescence
    • G01N21/645—Specially adapted constructive features of fluorimeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/2018—Scintillation-photodiode combinations
    • G01T1/20184—Detector read-out circuitry, e.g. for clearing of traps, compensating for traps or compensating for direct hits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H01L27/14658—X-ray, gamma-ray or corpuscular radiation imagers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • H04N23/73—Circuitry for compensating brightness variation in the scene by influencing the exposure time
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
    • H04N25/63—Noise processing, e.g. detecting, correcting, reducing or removing noise applied to dark current
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith
    • H04N25/71—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
    • H04N25/75—Circuitry for providing, modifying or processing image signals from the pixel array
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith
    • H04N25/76—Addressed sensors, e.g. MOS or CMOS sensors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H01L27/14627—Microlenses

Definitions

  • This technology relates to an imaging device.
  • the present invention relates to an imaging device including an imaging device that detects weak light, an electronic apparatus including the imaging device, and an imaging method.
  • CMOS Complementary Metal Oxide Semiconductor
  • This technology was created in view of these circumstances, and aims to improve the accuracy of photon counting.
  • the present technology has been made to solve the above-described problems, and the first side of the present technology is light that is incident on an imaging device in which a plurality of pixels are arranged and is a detection target of the number of photons.
  • the imaging apparatus includes a light uniformizing unit that substantially uniforms the distribution of incident light in a direction orthogonal to the optical axis and supplies the uniformed light to the imaging element. This brings about the effect that the incident light which is the detection target of the number of photons is made substantially uniform, and the uniformed light is made incident on the image sensor.
  • the image sensor performs digital determination on the number of incident photons by the uniformized light supplied to each of the plurality of pixels, and determines the determination result value of the digital determination as described above.
  • Output for each of the plurality of pixels sum the output determination result values for each of the plurality of pixels in units of frames, and calculate the number of photons of the incident light during the exposure period of the frame based on the summed sum value You may make it further provide the calculation part to calculate.
  • the number of incident photons of the uniformed light is digitally determined for each pixel, and the number of photons of the incident light is calculated based on the total value obtained by summing the determination result values of the digital determination in units of frames. .
  • the calculation unit calculates the number of photons of the incident light using difference correction information indicating a relationship between the number of photons actually incident on the plurality of pixels and the total value. You may make it calculate based on the said total value. Accordingly, there is an effect that the number of photons of incident light is calculated based on the total value using the difference correction information indicating the relationship between the number of photons actually incident on the plurality of pixels and the total value.
  • the image sensor performs binary determination as the digital determination
  • the calculation unit performs the calculation using the Poisson distribution or information related to a relation approximated to the Poisson distribution as the difference correction information. You may make it perform. This brings about the effect that the number of photons of the incident light is calculated based on the total value using the information related to the Poisson distribution or the relationship approximated to the Poisson distribution.
  • the calculation unit calculates the determination result value of the pixel having a large dark current based on pixel position information for identifying a pixel having a large dark current among the plurality of pixels.
  • the total value may be calculated by excluding it. Thereby, based on the pixel position information for identifying a pixel with a large dark current among a plurality of pixels, the determination result value of the pixel with a large dark current is excluded, and the total value is calculated.
  • the calculation unit may correct the total value based on a ratio between the number of pixels from which the determination result value is excluded and the total number of the plurality of pixels. This brings about the effect that the total value is corrected based on the ratio between the number of pixels from which the determination result value is excluded and the total number of pixels.
  • the imaging device performs binary determination as the digital determination
  • the calculation unit uses the difference information related to the Poisson distribution or the relationship approximated to the Poisson distribution to calculate the number of photons of the incident light. May be calculated based on the corrected total value.
  • the total value corrected based on the ratio between the number of pixels from which the determination result value is excluded and the total number of the plurality of pixels is further corrected using the difference information, and the number of photons is calculated. Bring.
  • the imaging device includes a plurality of pixel arrays that are independently driven, and the light uniformizing unit is provided in pairs for each of the plurality of pixel arrays. It may be. Accordingly, there is an effect that a plurality of imaging units each including a pair of the light uniformizing unit and the pixel array are provided in the imaging element.
  • the optical system further includes a dividing unit that substantially uniforms the distribution of the incident light in the orthogonal direction of the optical axis and divides the uniformed incident light into a plurality of incident lights.
  • the uniformizing unit may supply the incident light divided into the plurality to the pair of pixel arrays. Thereby, the uniformized incident light is divided, and the divided light is supplied to each imaging unit provided with a pair of light uniformizing units and a pixel array.
  • the plurality of pixel arrays have the same exposure period length and start timing, and each of the plurality of pixel arrays is supplied to each of the plurality of pixels in the pixel array.
  • a calculation unit that calculates the number of photons of the incident light during the exposure period based on the summed sum value may be further included.
  • a plurality of imaging units each provided with a pair of light uniformizing units and a pixel array are driven at the same timing, and a value obtained by summing up the total values in the plurality of imaging units is calculated as a total value in the exposure period. This brings about the effect.
  • the plurality of pixel arrays are classified into a plurality of groups having different exposure period start timings, and each of the plurality of pixel arrays is supplied to each of the plurality of pixels in the pixel array.
  • Digital determination is performed on the number of incident photons by the emitted light, the determination result value of the digital determination is output for each of the plurality of pixels, and the determination result value of each of the plurality of output pixels is summed in units of the group.
  • the second aspect of the present technology is a direction orthogonal to the optical axis of incident light that is an object of detection of the number of photons on an image sensor in which a plurality of pixels are arranged and is an object of detection of the number of photons.
  • the light uniformizing unit for substantially uniforming the distribution of light and supplying the uniformed light, and performing digital determination for each of a plurality of pixels with respect to the number of incident photons by the supplied light, and the determination result of the digital determination
  • the image sensor that outputs a value for each of the plurality of pixels and the output determination result value of each of the plurality of pixels are summed in units of frames, and the number of photons of the incident light in the exposure period of the frame is summed.
  • the electronic device includes a calculating unit that calculates based on the total value.
  • the incident light which is the detection target of the number of photons is made to be substantially uniform and incident on the image sensor, and the photon counting is performed based on the uniformed light.
  • a third aspect of the present technology provides a light homogenizer that substantially uniformizes the distribution of incident light, which is a detection target of the number of photons, in a direction orthogonal to the optical axis, and supplies the uniformized light.
  • a detection unit including a plurality of imaging units each including a plurality of pixels that perform digital determination on each of a plurality of pixels with respect to the number of incident photons by the supplied light and output a determination result value of the digital determination for each of the plurality of pixels.
  • This is a stimulated emission detection scanner.
  • the fourth aspect of the present technology provides an incident light that is a detection target of the number of photons to an imaging element in which a plurality of pixels are arranged and is orthogonal to an optical axis of the incident light that is a detection target of the number of photons. For each of the plurality of pixels with respect to the number of incident photons by the supplied light to each of the plurality of pixels, and a light uniformization procedure for supplying the uniformed light to the image sensor.
  • a calculation procedure for performing a digital determination and summing the determination result values of each of the plurality of pixels in units of frames, and calculating the number of photons of the incident light during the exposure period of the frame based on the summed sum value An imaging method comprising the steps of: Thereby, the incident light that is the detection target of the number of photons is made substantially uniform and incident on the image sensor, and the number of photons received by the uniformed light is digitally determined for each pixel, and the determination result value of this determination The summation is performed in frame units, and the number of photons of incident light is calculated based on the summed sum value.
  • FIG. 3 is a schematic diagram illustrating an example of a circuit configuration of a pixel 310 according to the first embodiment of the present technology.
  • FIG. 3 is a conceptual diagram illustrating an example of a functional configuration example of a determination circuit 113 and an operation example of the determination circuit 113 according to the first embodiment of the present technology.
  • FIG. 5 is a graph showing the relationship between the average number of photons incident on each pixel during a unit exposure period and the count probability in the first embodiment of the present technology. It is a figure showing typically an example of exposure operation and read-out operation of image sensor 110 of a 1st embodiment of this art.
  • An example of a detection head (detection head 101) to which the light detection device 10 according to the first embodiment of the present technology is applied and an example of a conventional detection head (detection head 191) to which a photomultiplier tube is applied are schematically illustrated.
  • FIG. It is a flowchart which shows an example of the process sequence when the photon detection apparatus 10 of 1st Embodiment of this technique performs photon counting operation
  • FIG. 501 It is a schematic diagram which shows an example of the module (imaging module 501) which mounted the imaging device (imaging device 500) provided with two or more imaging circuits. It is a conceptual diagram which shows an example of the detection head (detection head 502) to which the imaging module 501 in the 3rd Embodiment of this technique is applied. It is a conceptual diagram which shows an example of the classification into the four groups of the image pick-up circuit of the image pick-up element (image pick-up element 500) in 4th Embodiment of this technique. It is a figure showing typically an example of exposure operation and read-out operation for every group of image pick-up circuit 520 classified into four groups in a 4th embodiment of this art.
  • First embodiment imaging control: an example in which incident light is uniformized by a light uniformizing unit to perform photon counting
  • Second Embodiment Imaging Control: Example of performing photon counting by masking a pixel with a large dark current
  • Third Embodiment Imaging Control: Example in which a plurality of pixel array units are provided in one imaging element
  • Fourth Embodiment Imaging Control: Example in which a plurality of pixel array units are grouped and different exposure operations are performed for each group) 5.
  • FIG. 1 is a block diagram illustrating an example of a functional configuration related to the light detection device 10 according to the first embodiment of the present technology.
  • the photodetection device 10 is an imaging device that performs photon (photon) counting using a CMOS (Complementary Metal Metal Oxide Semiconductor) sensor, and includes a detection unit 100 and a data processing unit 120.
  • CMOS Complementary Metal Metal Oxide Semiconductor
  • the detection unit 100 converts light incident on the detection unit 100 into a digital signal, and includes a light uniformizing unit 200 and an image sensor 110.
  • the light homogenizer 200 irradiates the pixel array of the image sensor 110 with a substantially uniform distribution of light (photon count target light) incident on the detector 100 and substantially uniformed photon count target light. . That is, the light homogenizing unit 200 applies the same number of photon count target light incident on the incident surface (in the direction orthogonal to the optical axis of the image sensor 110) to each pixel of the pixel array of the image sensor 110. It plays the role of distributing so that it is incident one by one.
  • the light homogenizing unit 200 includes, for example, a kaleidoscope using reflection, an integrated lens such as a fly lens with a small lens, a diffractive optical element (DOE) using diffraction, fine particles that scatter light on glass or resin, This is realized by a light scattering material to which dots are added. It can also be realized by an optical fiber having a light uniforming function or a light guide in which a plurality of optical fibers having a light uniforming function are bundled. In addition, since the reason for making light uniform by the light uniformizing unit 200 will be described with reference to FIG. 6, description thereof is omitted here.
  • DOE diffractive optical element
  • the image sensor 110 photoelectrically converts incident light into an electrical signal to generate an image signal, and pixels are arranged in an array.
  • the image sensor 110 is realized by a CMOS (Complementary Metal Oxide Semiconductor) sensor, for example. Note that the image sensor 110 will be described with reference to FIGS.
  • CMOS Complementary Metal Oxide Semiconductor
  • the presence or absence of photon incidence on each pixel is binary-determined in the image sensor.
  • the image sensor 110 supplies data (digital data) indicating the binary determination result to the data processing unit 120.
  • the data processing unit 120 calculates the intensity (count value) of photon counting target light based on data (digital data) supplied from the image sensor 110.
  • the data processing unit 120 includes a counting unit 130 and a recording unit 140.
  • the counting unit 130 calculates the intensity (count value) of photon counting target light per frame based on the data supplied from the image sensor 110. For example, the count unit 130 calculates the count value per frame by adding the digital data values (0 or 1) of all the pixels. The count unit 130 supplies the calculated count value to the recording unit 140 and causes the recording unit 140 to record the count value.
  • the count unit 130 is an example of a calculation unit described in the claims.
  • a mask process for a pixel with a strong dark current and a correction process for a count value for a pixel with a strong dark current can be performed. Note that an example of performing mask processing for pixels with strong dark current and count value correction processing for pixels with strong dark current will be described in the second embodiment of the present technology, so the first embodiment of the present technology will be described. Now, an example in which dark current is not considered will be described.
  • the recording unit 140 records the count value supplied from the counting unit 130.
  • FIG. 2 is a conceptual diagram illustrating an example of a detection head (detection head 101) to which the light detection device 10 according to the first embodiment of the present technology is applied.
  • the detection head 101 receives light emitted from the detection target spot (detection spot 109) (which will be described here assuming fluorescence) and measures the intensity of the light.
  • a hole 103, a light uniformizing unit 200, and an image sensor 110 are provided.
  • digital data output from the image sensor 110 is supplied to the data processing unit 120 via the signal line 104.
  • the light uniformizing unit 200, the image sensor 110, and the data processing unit 120 shown in FIG. 2 have been described with reference to FIG.
  • a band-pass filter and a cut-off filter are arranged on the optical path so that the excitation light is shielded and only the fluorescence passes through the pinhole 103, but these are also omitted.
  • the condensing lens 102 condenses light, and condenses light incident on the incident surface of the condensing lens 102 out of the fluorescence emitted from the detection spot 109 in a pinhole (pinhole 103).
  • the pinhole 103 is a hole provided at a position where the fluorescence emitted from the detection target spot and passing through the condenser lens 102 is condensed again. Since the fluorescence generated outside the focus position (detection target spot) is not condensed on the pinhole 103, most of the fluorescence generated outside the focus position is shielded by the light shielding member that forms the pinhole 103. Thereby, the incidence
  • the fluorescence that has passed through the pinhole 103 is incident on the light uniformizing unit 200, and the light that is uniformized by the light uniformizing unit 200 is incident on the image sensor 110.
  • the fluorescence that has passed through the pinhole 103 is detected by a photomultiplier tube (PMT: PhotoMultiplier Tube) (see a in FIG. 8), but in the embodiment of the present technology, the photomultiplier tube Instead, the light uniformizing unit 200 and the image sensor 110 are provided.
  • PMT PhotoMultiplier Tube
  • the fluorescence intensity distribution in a wide inspection region can be detected by step-moving the detection head 101 and the excitation light source as shown in FIG. 2 relative to the subject.
  • FIG. 3 is a conceptual diagram illustrating an example of a basic configuration example of the image sensor 110 according to the first embodiment of the present technology.
  • the image sensor 110 includes a pixel array unit 300, a first vertical drive circuit 112, a determination circuit 113, a register 114, a second vertical drive circuit 115, and an output circuit 118.
  • the determination circuit and the register for processing the pixel signal driven by the second vertical drive circuit 115 are the determination circuit (the determination circuit 113) for processing the pixel signal driven by the first vertical drive circuit 112. ) And the register (register 114), the description is omitted.
  • the pixel array unit 300 includes a plurality of pixels (pixels 310) arranged in a two-dimensional matrix (n ⁇ m).
  • pixels 310 pixels arranged in a two-dimensional matrix (n ⁇ m).
  • n ⁇ m two-dimensional matrix
  • the pixels 310 of 128 rows ⁇ 128 columns are arranged in the pixel array unit 300.
  • a part of the pixels 310 of 128 rows ⁇ 128 columns is shown.
  • Half of the pixels 310 arranged in the pixel array unit 300 (pixels located in the upper half of the pixel array unit 300 in FIG. 3) have a control line (control line 330) from the first vertical drive circuit 112. Wired in rows.
  • control lines are wired from the second vertical drive circuit 115 in units of rows. Note that the circuit configuration of the pixel 310 will be described with reference to FIG.
  • a vertical signal line (vertical signal line 341) is wired to the pixel 310 in units of columns.
  • the vertical signal line 341 is wired as a separate line for each vertical drive circuit to which the pixel 310 is connected.
  • the vertical signal line 341 connected to the pixel to which the control line 330 is wired from the first vertical drive circuit 112 is connected to the determination circuit 113 facing the upper side of the pixel array unit 300.
  • the vertical signal line 341 connected to the pixel to which the control line 330 is routed from the second vertical drive circuit 115 is connected to the determination circuit 113 facing the lower side of the pixel array unit 300.
  • the first vertical drive circuit 112 supplies a signal to the pixel 310 via the control line 330 and sequentially scans the pixel 310 in units of rows in the vertical direction (column direction). As the first vertical drive circuit 112 performs selective scanning in units of rows, a signal is output from the pixels 310 in units of rows.
  • the control line 330 includes a pixel reset line 331 and a charge transfer line 332. The pixel reset line 331 and the charge transfer line 332 will be described with reference to FIG.
  • the second vertical drive circuit 115 is the same except that the pixel 310 to be controlled is different from the first vertical drive circuit 112, and thus the description thereof is omitted here.
  • the determination circuit 113 determines whether or not photons are incident on the pixel 310 based on the output signal supplied from the pixel 310 (binary determination). This determination circuit 113 is provided for each vertical signal line 341. That is, at the position facing the upper side of the pixel array unit 300, 128 pieces connected to 128 vertical signal lines 341 wired to pixels (64 rows ⁇ 128 columns) driven by the first vertical drive circuit 112, respectively. Determination circuit 113 is provided. Further, at the position facing the lower side of the pixel array unit 300, 128 pieces connected to 128 vertical signal lines 341 wired to pixels (64 rows ⁇ 128 columns) driven by the second vertical drive circuit 115, respectively. Determination circuit 113 is provided.
  • the determination circuit 113 supplies the determination result to the register 114 connected to each determination circuit 113.
  • the register 114 is provided for each determination circuit 113 and temporarily holds the determination result supplied from the determination circuit 113.
  • the register 114 sequentially outputs the determination results to be held to the output circuit 118 during the period in which the signal of the next row of pixels is read (reading period).
  • the output circuit 118 outputs a signal generated by the image sensor 110 to an external circuit.
  • FIG. 4 is a schematic diagram illustrating an example of a circuit configuration of the pixel 310 according to the first embodiment of the present technology.
  • the pixel 310 converts an optical signal that is incident light into an electrical signal by performing photoelectric conversion.
  • the pixel 310 amplifies the converted electric signal and outputs it as a pixel signal.
  • the pixel 310 amplifies an electric signal by an FD amplifier having a floating diffusion layer (floating diffusion: FD).
  • the pixel 310 includes a photodiode 311, a transfer transistor 312, a reset transistor 313, and an amplifier transistor 314.
  • the photodiode 311 has its anode terminal grounded and its cathode terminal connected to the source terminal of the transfer transistor 312.
  • the transfer transistor 312 has a gate terminal connected to the charge transfer line 332 and a drain terminal connected to the source terminal of the reset transistor 313 and the gate terminal of the amplifier transistor 314 via the floating diffusion (FD 322).
  • the reset transistor 313 has its gate terminal connected to the pixel reset line 331 and its drain terminal connected to the power supply line 323 and the drain terminal of the amplifier transistor 314.
  • the source terminal of the amplifier transistor 314 is connected to the vertical signal line 341.
  • the photodiode 311 is a photoelectric conversion element that generates an electric charge according to the intensity of light.
  • pairs of electrons and holes are generated by photons incident on the photodiode 311, and the generated electrons are accumulated.
  • the transfer transistor 312 transfers electrons generated in the photodiode 311 to the FD 322 in accordance with a signal (pulse) from the vertical drive circuit (the first vertical drive circuit 112 or the second vertical drive circuit 115).
  • the transfer transistor 312 becomes conductive when, for example, a signal (pulse) from the charge transfer line 332 supplied to its gate terminal is supplied to the gate terminal, and transfers electrons generated in the photodiode 311 to the FD 322.
  • the reset transistor 313 is for resetting the potential of the FD 322 in accordance with a signal (reset pulse) supplied from the vertical drive circuit (the first vertical drive circuit 112 or the second vertical drive circuit 115).
  • the reset transistor 313 becomes conductive when a reset pulse is supplied to the gate terminal via the pixel reset line 331, and a current flows from the FD 322 to the power supply line 323.
  • a reset potential As a result, electrons accumulated in the floating diffusion (FD 322) are extracted to the power source, and the floating diffusion is reset (hereinafter, this potential is referred to as a reset potential). Note that when the photodiode 311 is reset, the transfer transistor 312 and the reset transistor 313 are simultaneously turned on.
  • a potential (power supply) flowing through the power supply line 323 is a power supply used for resetting and a source follower, and for example, 3 V is supplied.
  • the amplifier transistor 314 amplifies the potential of the floating diffusion (FD 322) and outputs a signal (output signal) corresponding to the amplified potential to the vertical signal line 341.
  • a signal output signal
  • the amplifier transistor 314 outputs an output signal (hereinafter referred to as a reset signal) corresponding to the reset potential vertically.
  • the amplifier transistor 314 outputs an output signal (hereinafter referred to as an accumulated signal) corresponding to the amount of transferred electrons to the vertical signal. Output to line 341.
  • the basic circuit and operation mechanism of the pixel as shown in FIG. 4 are the same as those of a normal pixel, and various other variations are possible.
  • the pixel assumed in the present technology is designed so that the conversion efficiency is significantly higher than that of the conventional pixel.
  • the pixel is designed so that the parasitic capacitance (parasitic capacitance of the FD 322) of the gate terminal of the amplifier (amplifier transistor 314) constituting the source follower is effectively reduced to the limit.
  • This design can be performed by, for example, a method of devising the layout or a method of feeding back the output of the source follower to a circuit in the pixel (see, for example, JP-A-5-63468 and JP-A-2011-119441).
  • the parasitic capacitance is reduced so that a sufficiently large output signal is output to the vertical signal line 341 even if the number of electrons accumulated in the FD 322 is small.
  • the magnitude of this output signal only needs to be sufficiently larger than the random noise of the amplifier transistor 314. If the output signal when one photon is accumulated in the FD 322 becomes sufficiently larger than the random noise of the amplifier transistor 314, the signal from the pixel is quantized and the number of accumulated photons in the pixel can be detected as a digital signal. .
  • the output signal is sufficiently larger than the random noise, so in principle one photon Can be detected.
  • the noise after the output of the output signal by the amplifier transistor 314 can be made substantially zero.
  • binary determination is performed on a pixel array of 128 rows ⁇ 128 columns, it is possible to photon count up to a maximum of 16,384 (128 ⁇ 128) photons.
  • FIG. 4 illustrates an example of a pixel in which one pixel can be detected by designing the pixel so that the parasitic capacitance is effectively reduced to the minimum
  • the present invention can be similarly implemented by a pixel that amplifies electrons obtained by photoelectric conversion within the pixel.
  • a pixel in which a plurality of stages of CCD multiplication transfer elements are embedded between the photodiode in the pixel and the gate terminal of the amplifier transistor is conceivable (see, for example, JP 2008-35015 A).
  • the photoelectrically converted electrons are multiplied by about 10 times in the pixel.
  • one-photon detection can be performed by multiplying the image of electrons in a pixel, and an image sensor in which such a pixel is arranged can be used as the image sensor 110.
  • the determination circuit 113 that determines whether or not photons are incident on the pixel 310 based on the output signal supplied from the pixel 310 will be described with reference to FIG.
  • FIG. 5 is a conceptual diagram illustrating an example of a functional configuration example of the determination circuit 113 and an example of an operation example of the determination circuit 113 according to the first embodiment of the present technology.
  • an ACDS (Analog Correlated Double Sampling) unit 410 As a functional configuration of the determination circuit 113, an ACDS (Analog Correlated Double Sampling) unit 410, a DCDS (Digital CDS; digital correlation double sampling) unit 420, and a binary determination unit 430. Is shown.
  • the vertical signal line 341 connected to the determination circuit 113, a part of the pixel 310 connected to the vertical signal line 341, and the pixel array unit 300 have the functional configuration of the determination circuit 113. Show together.
  • the ACDS unit 410 performs noise removal by analog CDS, and includes a switch 412, a capacitor 413, and a comparator 411.
  • the switch 412 is a switch for connecting the vertical signal line 341 to either an input terminal for inputting a reference voltage to the comparator 411 or an input terminal for inputting a signal to be compared to the comparator 411.
  • the switch 412 connects the vertical signal line 341 to an input terminal (a left terminal to which the capacitor 413 is connected) for inputting a reference voltage.
  • the comparator 411 outputs the result of analog CDS
  • the switch 412 connects the vertical signal line 341 to an input terminal (right terminal without a capacitor) for inputting a signal to be compared.
  • the capacitor 413 is a storage capacitor for sample-holding the reset signal of the pixel 310.
  • the comparator 411 outputs the difference between the sampled and held signal and the signal to be compared. That is, the comparator 411 outputs the difference between the reset signal sampled and held and the signal (accumulated signal or reset signal) supplied from the vertical signal line 341. That is, the comparator 411 outputs a signal from which noise generated in the pixel 310 such as kTC noise is removed.
  • the comparator 411 is realized by an operational amplifier with a gain of 1, for example.
  • the comparator 411 supplies the difference signal to the DCDS unit 420.
  • the difference signal between the reset signal and the reset signal is referred to as no signal
  • the difference signal between the reset signal and the accumulation signal is referred to as a net accumulation signal.
  • the DCDS unit 420 performs noise removal by digital CDS, and includes an AD (Analog Digital) conversion unit 421, a register 422, a switch 423, and a subtractor 424.
  • AD Analog Digital
  • the AD conversion unit 421 performs AD conversion on the signal supplied from the comparator 411.
  • the switch 423 is a switch for switching the supply destination of the signal after AD conversion generated by the AD conversion unit 421.
  • the switch 423 supplies the signal to the register 422 and causes the register 422 to latch (hold) it.
  • the offset value of the AD conversion unit 421 is held in the register 422.
  • the switch 423 supplies this signal to the subtractor 424 when the AD conversion unit 421 outputs the result of AD conversion of the net accumulated signal (digital net accumulated signal).
  • the register 422 holds the result of no signal AD conversion.
  • the register 422 supplies the non-signal A / D conversion result (digital non-signal) held to the subtractor 424.
  • the subtractor 424 subtracts the digital no-signal value from the digital net accumulated signal value.
  • the subtractor 424 supplies the subtraction result (net digital value) to the binary determination unit 430.
  • the binary determination unit 430 performs binary determination (digital determination).
  • the binary determination unit 430 compares the output (net digital value) of the subtractor 424 with the reference signal (REF) to make a binary determination as to whether or not a photon is incident on the pixel 310, and the determination result (FIG. 5 indicates “BINOUT”).
  • FIG. 5 b shows a flowchart showing an example of the operation example of the determination circuit 113.
  • corresponds to the frame surrounding each structure shown by a of FIG. That is, the procedure indicated by the double frame indicates the procedure of the pixel 310, the procedure indicated by the long dashed line frame indicates the procedure of the ACDS unit 410, and the procedure indicated by the short dashed line frame indicates the procedure of the DCDS unit 420.
  • the procedure indicated by the thick solid frame indicates the procedure of the binary determination unit 430.
  • the ACDS processing by the ACDS unit 410 is not illustrated, and will be described together in a procedure when the DCDS unit 420 performs AD conversion.
  • the potential of the gate terminal of the amplifier transistor 314 (the potential of the FD 322) is reset, and a reset signal is output to the vertical signal line 341 (step 441).
  • the reset signal output from the pixel 310 is sampled and held by the capacitor 413 of the ACDS unit 410 (step 442). Thereafter, a difference signal (no signal) between the reset signal sampled and held and the reset signal output from the pixel 310 is AD-converted by the AD conversion unit 421 of the DCDS unit 420 (step 443).
  • the AD-converted no signal includes noise generated by the comparator 411 and the AD converter 421, and a value for canceling (offset) these noises is digitally detected. .
  • the result of this AD conversion without signal is held in the register 422 as an offset value (step 444).
  • the electrons accumulated in the photodiode 311 are transferred to the FD 322, and an accumulation signal is output from the pixel 310 (step 445).
  • a difference signal (net accumulated signal) between the sampled and held reset signal and the accumulated signal output from the pixel 310 is AD converted by the AD converting unit 421 of the DCDS unit 420 (step 446). Note that the AD conversion result includes noise generated by the comparator 411 and the AD conversion unit 421.
  • the subtracter 424 outputs a value obtained by subtracting the result of the non-signal AD conversion (first time) held in the register 422 from the value of the AD conversion result (second time) of the net accumulated signal. (Step 447). As a result, noise (offset component) caused by the comparator 411 and the AD conversion unit 421 is canceled, and the digital value (net digital value) of only the accumulated signal output from the pixel 310 is output.
  • the reference signal (REF) is near an intermediate value between the digital value of the signal (no signal) output from the pixel 310 when no photon is incident and the digital value of the signal (no signal) output from the pixel 310 when the photon is incident. (For example, “50” between “0” and “100” is a reference signal).
  • the value of the digital value output from the subtractor 424 exceeds the value of the reference signal (REF)
  • the value “1” is set as “photon incident”.
  • Signal (BINOUT) is output.
  • a signal (BINOUT) having a value of “0” is output as “no photon incidence”. That is, the image sensor 110 outputs the presence or absence of photon incidence as a digital value (0 or 1) as a binary determination result.
  • the description has been made on the assumption that binary determination (binary determination) between “with photon incidence” and “without photon incidence” has been made, but by preparing a plurality of reference signals (REF). Determination of two or more values is possible. For example, two systems of reference signals (REF) are prepared, and one system is set to an intermediate value between a digital value when the number of photons is “0” and a digital value when the number of photons is “1”. The other system is set to an intermediate value between the digital value when the number of photons is “1” and the digital value when the number of photons is “2”.
  • REF reference signals
  • the signal output from the pixel 310 is determined as a digital value by the determination circuit 113, so that it is compared with a conventional image sensor that handles analog output (1024 gradations for 10-bit data). Thus, it is almost completely unaffected by noise during transmission.
  • FIG. 6 is a graph showing the relationship between the average number of photons incident on each pixel during a unit exposure period and the count probability in the first embodiment of the present technology.
  • the photon is uniformly and randomly incident on each pixel of the image sensor 110 by the light uniformizing unit 200 on each pixel of the image sensor 110. It is assumed that photons are incident uniformly and randomly over time.
  • the average number of photons incident on each pixel within the unit exposure period (average photon number) and the probability that the incident photons are counted (determined as “1” by the determination circuit 113) (count probability)
  • count probability The relation to is in accordance with the Poisson distribution.
  • P (k) is a probability that photon incidence occurs k times (k photons are incident) in the unit pixel within the unit exposure period.
  • ⁇ is the average number of photons incident on the unit pixel (average photon number) within the unit exposure period.
  • E is the base of the natural logarithm ( ⁇ 2.718).
  • the probability P (k) of the above-described formula 1 indicates the probability that the number of incident photons is the number k of photons when the number of photons incident on each pixel during the unit exposure period is the average number of photons ⁇ . .
  • the average photon number and the count probability explain the relationship.
  • the determination circuit 113 of the image sensor 110 binaryly determines whether or not a photon is incident on a pixel.
  • the digital value output from the determination circuit 113 is “0”
  • the number of photons incident on the unit pixel is zero. That is, the probability that the digital value is “0” is “0.8105”, which is the probability of the case where the number of photons incident on the unit pixel is zero.
  • the probability that the digital value is “1” (count probability) is “0.1894”, which is the sum of the probabilities of one or more photons incident on the unit pixel.
  • the count probability “0.1894” indicates that about 10% of the incident photons are not counted (count loss). This count loss is caused by counting “1” when two or more photons are incident on a unit pixel within the unit exposure period. Therefore, the count loss increases as the average photon number ⁇ increases.
  • the average photon number ⁇ is “0.21”.
  • the relationship between the average photon number ⁇ and the count probability is such that the photons are spatially and temporally uniform. It is unique when incident randomly. That is, when the vertical axis is the axis indicating the count probability and the horizontal axis is the average number of photons incident on each pixel during the unit exposure period, the relationship between the count probability and the average photon number is represented by the solid line ( The relationship is shown by a line 451).
  • the position of the average photon number shown with a chain line shows the position (10% detection loss position) where about 10% of the incident photons are lost.
  • a count loss of about 10% is allowed and linearity can be guaranteed when the average number of photons is “0.21” or less. If this is viewed from the side of the digital output value generated by the image sensor 110, that is, if the count probability in the digital value generated by the image sensor 110 is "0.1894" or less, the illuminance and exposure conditions that can guarantee linearity It is determined that the image was taken. On the other hand, when the count probability exceeds “0.1894” (the range indicated by the compression region 453 in FIG. 6), it is determined that the count loss is large and linearity cannot be guaranteed.
  • the count value can be corrected.
  • a count probability (a ratio of pixels having a value of “1” in all pixels) is calculated based on the digital value generated by the image sensor 110, and the relationship shown in the table of FIG.
  • the average number of photons is calculated from the data shown.
  • the number of photons incident on the image sensor 110 is calculated from the calculated average number of photons.
  • the imaging plate stores an X-ray latent image transmitted through the human body.
  • the imaging plate emits light (stimulated light emission) according to the latent image of X-rays when irradiated with excitation light by a fluorescent scanner.
  • the fluorescent scanner detects the generated photostimulated luminescence, thereby acquiring an X-ray photograph with a wide dynamic range without using a film or dark room development.
  • FIG. 7 is a diagram schematically illustrating an example of the exposure operation and the read operation of the image sensor 110 according to the first embodiment of the present technology.
  • the horizontal direction is a direction indicating a time axis
  • the vertical direction is a direction indicating a row from which a signal is read (reading row address)
  • signal reading timings (reading timings 462 to 464) of the image sensor 110 are illustrated. Is schematically shown. 7A shows a period from the start to the end of exposure (unit exposure period 466) and excitation light irradiation timing (excitation light irradiation timing 467).
  • the readout timing at which light generated by excitation at the excitation light irradiation timing 467 is detected is shown by making the oblique lines indicating the read timings 462 to 464 thick bold lines.
  • the readout timing at which light generated by this excitation is detected corresponds to the readout timing 463. That is, all the accumulated signals generated by the pixels by the light generated by the excitation are read from the reading of the first row at the reading timing 463 (left end of the reading timing 463) to the reading of the last row (right end of the reading timing 463). .
  • the position of the detection target (detection spot) is moved immediately after the previous reading is completed (the right end of the reading timing 462). Then, the moved detection spot is irradiated with an excitation light pulse (excitation light irradiation timing 467).
  • excitation light irradiation timing 467 an excitation light pulse
  • photostimulated light emission occurs according to the amount of X-ray absorption (latent image) at the detection spot.
  • the generation of light (fluorescence) due to this stimulated emission attenuates in about 1 ⁇ sec. 1 microsecond is shorter than the readout period for one row of the image sensor 110. For example, when the time for one round of reading (the time from the left end to the right end of the read timing 463) is 320 ⁇ sec, 1 ⁇ sec is very short, and a large number of photons are generated almost simultaneously.
  • the photons incident on the condenser lens 102 are irradiated on the pixel array unit 300 of the image sensor 110 substantially uniformly and randomly by the light uniformizing unit 200.
  • photons are dispersed and received by the pixels 310 of 128 rows ⁇ 128 columns, and electrons are accumulated.
  • a read timing read timing 463
  • an accumulation signal corresponding to the accumulated electrons is sequentially read for each row.
  • the horizontal axis is the same time axis as in FIG. 7a, and the vertical axis is the axis indicating the number of counts (count number) of the digital value “1”. It is shown schematically. In addition, since all 64 lines (128 lines / 2) cannot be displayed, the number of lines (number of bars) is a schematic one.
  • FIG. 7 b shows a diagram that is omitted, reading out 64 times at the read timing 463 (reading 128 rows in two systems) completes the reading of all the rows, and the image sensor 110. All incident photons on the pixel array unit 300 are read out.
  • 7C and 7D show a case in which excitation light is irradiated while readout for each row is sequentially performed in the image sensor 110 (while an intermediate row is being read out).
  • FIG. 7C schematically shows the signal readout timing (readout timings 472 to 475) of the image sensor 110, as in FIG. 7a. Further, in FIG. 7d, the count number for each read row is schematically shown as in FIG. 7b. Note that the unit exposure period 476 and the excitation light irradiation timing 477 in FIG. 7C correspond to the unit exposure period 466 and the excitation light irradiation timing 467 in FIG. Further, the count readout period 479 by the stimulated light in FIG. 7D corresponds to the count readout period 469 by the stimulated light in FIG. 7B.
  • the unit exposure period shown in FIGS. 7A and 7B can be shortened by resetting the photodiode at a timing different from the readout timing. Further, this unit exposure period can be extended by providing an extra blank period that does not provide any interval between the read timing of the immediately preceding cycle and the read timing of the current cycle.
  • the unit exposure period (unit exposure period 476) in FIG. 7c indicates an exposure period (normal exposure period) that is neither shortened nor extended.
  • a unit exposure period (unit exposure period 466) in FIG. 7A indicates an extended exposure period.
  • the adjustment of the unit exposure period functions as a diaphragm for adjusting the amount of incident light with respect to light irradiation that lasts substantially uniformly over time.
  • reading operation from the image sensor 110 will be described using numerical values.
  • reading of each row is sequentially performed in a cyclic manner. As shown in FIG. 3, since two rows (two systems) are read out simultaneously, 128 rows make a round with 64 times (cycles) of reading. Since the photodiode is reset when the accumulated charge is transferred for reading, the exposure period is between reading and reading. This exposure period is also an accumulation period of photoelectrically converted charges.
  • the basic unit of the exposure period of each pixel is 320 ⁇ s (5 ⁇ s ⁇ 64 cycles) in which reading is completed. In this case, 3125 cycles (1 sec / 320 ⁇ sec (0.00032 sec)) are read out per second.
  • the photons to be detected are incident almost instantaneously, so that the temporal element is ignored and only the in-plane uniformity and randomness are guaranteed.
  • the upper limit of the number of incident photons to the pixel array unit that can guarantee linearity is indicated by the number of counts in a period in which reading from the pixels is completed (a period corresponding to reading of one frame), 3440 ( 128 ⁇ 128 ⁇ 0.21). If correction by Poisson distribution is added to this, the dynamic range is expected to be improved by an order of magnitude.
  • the data output rate from the image sensor 110 Since the image sensor 110 reads out two rows of 128 columns of pixels simultaneously, 256 (bit) binaries are output simultaneously. Since the reading of one row is 5 ⁇ s, the data output rate is 51 Mbps (256 bits / 5 ⁇ s (5 ⁇ 10 ⁇ 6 seconds)).
  • This is a general CPU (Central Even in a system using a processing unit, it is a data output rate at which data from a large number of image sensors can be simultaneously received and processed in parallel.
  • a counter is provided in the output circuit of the image sensor 110 (see the output circuit 118 in FIG. 3), and only the total value of the count is output every time the entire pixel array is read out (one frame is read out). If this is done, the output data rate will be extremely low.
  • the performance of the imaging device 110 assumed in the above description is roughly estimated with a certain margin with reference to the performance of the current general CMOS image sensor.
  • CMOS image sensor since signals from pixels are read by sequentially switching rows to be read, there is a minimum time required until the next reading. For this reason, in general light detection, a photon counter using a semiconductor imaging chip such as a CMOS image sensor has a considerably low time resolution of light detection in each pixel operation, and is greatly inferior to a photomultiplier tube.
  • the light uniformizing unit 200 causes the incidence of photons to be random and uniform, and randomly and uniformly irradiates a large number of planarly integrated pixels. . Therefore, for example, in a counter head using a photomultiplier tube, all photons incident on a single light receiving surface are photon-counted only with time resolution, whereas the photodetection device 10 shares them uniformly with a large number of pixels. To do. As a result, the light homogenization unit 200 guarantees that the incidence of photons on one pixel is very low. Thereby, the count accuracy and dynamic range of the photodetection device 10 become higher than the count accuracy and dynamic range of the photomultiplier tube.
  • the photodetection device 10 can compensate for the low time resolution with the spatial resolution of the light receiving surface in an equivalent form.
  • the photodetection device 10 includes a determination device (determination circuit 113) mounted on a semiconductor imaging chip (imaging device 110), and digitally determines the amount of incident light for each pixel. Enables counting accuracy and dynamic range to surpass photomultiplier tubes.
  • the AD conversion circuit is speeded up, three or more lines are simultaneously selected and processed in parallel, or a super-high parallel using a three-dimensional structure (for example, (See JP 2011-71958).
  • a three-dimensional structure for example, (See JP 2011-71958).
  • FIG. 8 shows an example of a detection head (detection head 101) to which the photodetection device 10 according to the first embodiment of the present technology is applied, and an example of a conventional detection head (detection head 191) to which a photomultiplier tube is applied.
  • FIG. 8 shows an example of a detection head (detection head 101) to which the photodetection device 10 according to the first embodiment of the present technology is applied, and an example of a conventional detection head (detection head 191) to which a photomultiplier tube is applied.
  • FIG. 8a shows an example of a detection head 191 to which a conventional photomultiplier tube is applied.
  • the detection head 191 includes a condenser lens 192, a pinhole 193, a photomultiplier tube 195, an AD conversion unit 197, and a data processing unit 198.
  • a detection spot 199 is shown on the left side of the condenser lens 192.
  • the condensing lens 192 and the pinhole 193 are the same as the condensing lens 102 and the pinhole 103 shown in FIG.
  • the photomultiplier tube 195 amplifies electrons generated by photoelectric conversion by avalanche and outputs the amplified result as an analog pulse.
  • the photomultiplier tube 195 requires a high voltage for accelerating the electrons in order to amplify the electrons.
  • the photomultiplier tube 195 supplies the generated analog pulse (analog signal) to the AD conversion unit 197 via the signal line 196.
  • the AD conversion unit 197 converts the analog pulse supplied from the photomultiplier tube 195 into a digital value and outputs it as a digital value for each sample section.
  • the AD conversion unit 197 supplies the digital value to the data processing unit 198.
  • the data processing unit 198 calculates the intensity of light to be detected based on the digital value supplied from the AD conversion unit 197. For example, the data processing unit 198 tabulates the digital values output from the AD conversion unit 197 for each fixed sample period, and uses the summation result as the fluorescence intensity of the detection spot 199.
  • the conventional detection head uses a photomultiplier tube.
  • Conventional detection heads are expensive because photomultiplier tubes are expensive.
  • an apparatus for supplying a high voltage is also required.
  • an AD conversion unit 197 is necessary.
  • FIG. 8b shows an example of a detection head (detection head 101) to which the light detection device 10 according to the first embodiment of the present technology is applied. Note that the detection head 101 shown in FIG. 8b is the same as that shown in FIG. 2, and thus detailed description thereof is omitted here.
  • a digital value signal (digital signal) is output from the image sensor 110. Since a digital signal is output in this way, it is less susceptible to noise than an analog signal.
  • FIG. 9 is a flowchart illustrating an example of a processing procedure when the photodetection device 10 according to the first embodiment of the present technology performs a photon counting operation.
  • step S901 the light of the number of photons to be detected (photon count target) is incident on the light uniformizing unit 200 of the detecting unit 100 (step S901). Subsequently, the distribution of the light incident on the light homogenizer 200 is uniformized by the light homogenizer 200 (step S902). Then, the uniformized light enters the pixel array unit 300 of the image sensor 110, and then the digital determination of the number of photons incident on the pixel is performed for each pixel by the determination circuit 113 based on the accumulation signal for each pixel. (Step S903).
  • step S902 is an example of a light homogenization procedure described in the claims.
  • Step S903 is an example of a determination procedure described in the claims.
  • step S904 is an example of a calculation procedure described in the claims.
  • the light uniformizing unit 200 by providing the light uniformizing unit 200, it is possible to irradiate the pixel array unit 300 of the image sensor 110 with light having a uniform photon distribution. That is, by providing the light uniformizing unit 200, light suitable for photon counting (light having a uniform photon distribution) can be supplied to the imaging device. Thereby, according to 1st Embodiment of this technique, the precision of photon counting can be improved.
  • Second Embodiment> The first embodiment of the present technology has been described on the assumption that all of the pixels in the pixel array unit are suitable for photon counting. However, at present, it is difficult to create all pixels in a CMOS image sensor as pixels having uniform properties. For example, a pixel with a large leak current (dark current) generated even in a dark state is not suitable for photon counting.
  • FIG. 10 is a diagram schematically illustrating a relationship between the magnitude of dark current (dark current level) generated in the pixel 310 according to the second embodiment of the present technology and the number of pixels 310 (pixel existence probability). It is.
  • the horizontal axis is the axis indicating the dark current level (logarithm), and the vertical axis is the axis indicating the pixel existence probability (logarithm). (Characteristic 490) is shown.
  • dark current will be described.
  • a slight leak current (dark current) is generated even in a dark state.
  • the leak current is generated via the leak current corresponding to the size of the recombination center.
  • a leakage current is generated even when a charge leak occurs in the floating diffusion (FD 322 in FIG. 2) that is in a floating state during the read operation period.
  • These leak currents are dark counts that are counted when no photons are incident during photon counting, which causes a deterioration in detection accuracy.
  • This dark current is known to vary greatly from pixel to pixel.
  • This variation characteristic is shown in the graph shown in FIG.
  • a characteristic 490 shown in this graph indicates the number of generated pixels for each dark current level. That is, as indicated by the characteristic 490, the number of pixels (existence probability) with almost no leakage current is the largest. And the number (existence probability) decreases as the leak current increases. For example, when the degree of dark current in the image sensor 110 is an average of about 0.5 electron leaks per pixel, most of the leaks are caused by about 10% of pixels with large dark current and poor performance. ing.
  • the relationship between the image sensor 110 according to the embodiment of the present technology and a pixel having a large dark current level will be described.
  • Light (fluorescence) from the detection target is made uniform by the light uniformizing unit 200 and then irradiated to each pixel of the pixel array unit 300 of the image sensor 110. Since the light to be detected is made uniform by the light uniformizing unit 200, the arrangement (distribution state) of the pixels having a large dark current level in the pixel array unit 300 does not affect the detection result, and the pixels having the large dark current level are not affected. Only the quantity matters.
  • the count value by the pixel having a large dark current level is ignored if the ratio of the pixels having a large dark current level is 10% or less. (Disabling) makes it possible to significantly reduce the dark count. In addition, since only the count value due to the pixel having a large dark current level is ignored, the dark count can be greatly reduced without substantially deteriorating the detection range or accuracy.
  • the total number of pixels (number of effective pixels) of the pixel array unit 300 is M and the number of pixels whose dark current level is worse than a predetermined standard is N.
  • N the number of pixels whose dark current level is worse than a predetermined standard.
  • the positions of N pixels are detected, and information about the positions (mask pixel position information) is recorded in the count unit 130.
  • the count value of N pixels whose positions are recorded is invalidated (masked), and the number of received photons per frame (per exposure period) is calculated. To do. That is, the binary determination result of these pixels is set to “0”, and the count values of all the pixels in the pixel array unit 300 are summed to calculate the number of received photons per unit exposure period.
  • the ratio of the masked pixel (N) to the effective pixel number M is known, the number of received photons per unit exposure period can be corrected. This correction is performed, for example, by multiplying the total count by M / (MN).
  • FIG. 11 is a flowchart illustrating an example of a detection processing procedure when the light detection device 10 according to the second embodiment of the present technology performs a mask target pixel detection operation.
  • imaging in the dark state is performed a plurality of times (for example, 1000 times), and the total count of dark counts is calculated for each pixel by adding the count results of the plurality of times of imaging for each pixel (step S911).
  • imaging is performed with an accumulation period of 33 msec at an ambient temperature of 60 ° C. (the dark current increases as the temperature increases).
  • a pixel having a total dark count greater than or equal to a specified value (threshold value) is determined as a high dark current pixel (mask target pixel), and the address information of the determined pixel is held in the count unit 130 (step S912).
  • a specified value for example, when the number of effective pixels is 128 rows ⁇ 128 columns, a memory area of about 2 kbytes is provided in the count unit 130, and pixel addresses and memory addresses are associated with each other in a one-to-one correspondence. “1” is recorded in the current pixel, and “0” is recorded in the normal pixel.
  • step S912 the detection processing procedure is finished.
  • FIG. 11 demonstrated the example which hold
  • the mask pixel position information may be prepared by the time when photon counting is executed.
  • a mask target pixel detection operation may be performed in a pre-shipment inspection of a semiconductor imaging chip (imaging device 110) and recorded in a nonvolatile memory provided in the semiconductor imaging chip.
  • the data processing unit 120 for example, the fluorescence inspection system
  • the fluorescence inspection system that processes the signal from the image sensor 110 acquires the mask pixel position information from the semiconductor imaging chip before the photon counting is performed, and the acquired Use information by copying it to internal memory.
  • a mask target pixel detection operation is performed without irradiating excitation light. Pixel position information may be generated.
  • the mask target pixel detection operation function is mounted inside the semiconductor imaging chip as one of the operation modes, the image sensor 110 acquires the address of the mask target pixel, and the acquired address is subjected to data processing. You may make it provide the function notified to a part.
  • FIG. 12 is a flowchart illustrating an example of a processing procedure when the photon detection device 10 according to the second embodiment of the present technology performs a photon counting operation with a mask.
  • step S921 it is determined whether or not photon detection is to be executed using the image sensor 110 (step S921), and if it is determined not to be executed, the process waits until it is executed.
  • the binary determination result (digital value) of each pixel in the readout target row (target row) in the image sensor 110 can identify the pixel address.
  • the state is output for each pixel (step S922). For example, when two rows are selected in one reading, the presence or absence of photon incidence in each pixel arranged in the two rows is output as a binary data stream.
  • a pixel (determination target pixel) to be subjected to mask determination is set by the count unit 130 (step S923).
  • the mask pixel position information is referred based on the set address of the determination target pixel, and information indicating whether or not the determination target pixel is the mask target pixel is referred to by the count unit 130 (step S924). ).
  • the counting unit 130 determines whether or not the pixel is a mask target pixel (step S925). If it is determined that the pixel is a mask target pixel, the process proceeds to step S927.
  • step S926 if it is determined that the pixel is not a mask target pixel (step S926), the binary determination result (“0” or “1”) of the determination target pixel is added to the total count (photon count value per frame). If it is determined that the pixel is a mask target pixel, step S926 is skipped and the process proceeds to step S927 to perform mask processing (masking) in which the binary determination result of the mask target pixel is invalidated.
  • the counting unit 130 determines whether or not all the pixels in the target row are mask target pixels (step S927). If it is determined that determination has not been performed for all the pixels in the target row (step S927), the process returns to step S923, and a new determination target pixel is set from the pixels for which determination has not been performed.
  • step S927 if it is determined that the mask target pixel has been determined for all the pixels in the target row (step S927), whether or not the mask target pixel has been determined for all the pixel rows of the image sensor 110. Is determined by the counting unit 130 (step S928). If it is determined that the process has not been performed for all the rows (step S928), the next row is set as a read target row (step S929). Then, after step S929, the process returns to step S922, and the output of the binary determination result from the image sensor 110 and the determination of the mask target pixel are repeated. Thus, the mask target pixel is determined for the pixels of one frame, and the binary determination results of the normal pixels (pixels not to be masked) are integrated.
  • the count unit 130 corrects the total count performed according to the number of mask target pixels. (Step S931). This correction is performed, for example, by multiplying the total count by M / (MN) according to the ratio of the mask target pixel number N and the total effective pixel number M, as shown in FIG.
  • step S932 the total number of counts that have been corrected is output as a detection result of photon counting (step S932), and the processing procedure of the photon counting operation with a mask ends.
  • the accuracy of photon counting can be improved by masking a pixel having a large dark current.
  • the correction of the total number of counts has been described assuming only the correction of the total number of counts based on the number of mask target pixels.
  • the present invention is not limited to this.
  • the accuracy of the photon counting detection result can be further improved.
  • the average number of photons is obtained from the count probability (the total number of counts / the number of effective pixels).
  • the total number of counts with corrected count loss can be obtained. In this case, since the substantial decrease in the number of effective pixels due to masking has already been corrected in step S931, it can be ignored.
  • the present invention is not limited to this.
  • the processing procedure of the photon counting operation with a mask is performed in the image sensor 110. Everything is done in Even in this case, the accuracy of the photon counting detection result can be further improved by correcting the count value according to the Poisson distribution in the semiconductor imaging chip.
  • FIG. 13 is a conceptual diagram illustrating an example of an image sensor (image sensor 500) including a plurality of pixel array units according to the third embodiment of the present technology.
  • FIG. 13 a top view of the image sensor 500 will be described assuming an XY axis where the vertical direction is the Y axis and the horizontal direction is the X axis.
  • imaging circuit 520 eight circuits (hereinafter referred to as imaging circuit 520) shown in the imaging device 110 in FIG. 3 are provided on a single semiconductor imaging chip (imaging device 500). Yes.
  • the image sensor 500 is provided with eight pixel array units (see the pixel array unit 300 in FIG. 3) that are driven independently.
  • the eight image pickup circuits 520 are provided with light uniformizing sections 530, respectively.
  • pads for exchanging signals with an external device are arranged at the ends of the image sensor 110 (upper side and lower side in FIG. 13).
  • power supply and synchronization signal input pads are wired so as to be shared by eight image pickup circuits 520, and digital data (bit stream of binary determination results) generated by the eight image pickup circuits 520 is supplied from independent pads. Wired to separate pads for output.
  • the eight imaging circuits 520 operate in parallel at the same time, and the photon count result is output from the output pad corresponding to each.
  • FIG. 14 is a schematic diagram illustrating an example of a module (imaging module 501) on which an imaging device (imaging device 500) including a plurality of imaging circuits is mounted.
  • FIG. 14 a cross-sectional view of the imaging module 501 will be described with the vertical direction as the Z axis and the horizontal direction as the X axis.
  • FIG. 14 shows an imaging module 501 in which the imaging element 500 is mounted using an LGA (Land Grid Array) type package. Since it is an LGA package, pads (pads 541) are arranged in a lattice pattern on the bottom surface of the package (package 540), and the pads 541 and the pads 510 of the image sensor 500 are connected to each other via lead wires. .
  • LGA Land Grid Array
  • an opening window (connector 531) is provided for each of the plurality of imaging circuits 520, and a light uniformizing unit 530 is provided between the connector 531 and the imaging circuit 520.
  • the connector 531 can be welded with an optical fiber, and the light to be detected is guided to the light uniformizing unit 530 by the optical fiber.
  • Each imaging circuit 520 of the imaging module 501 shown in FIG. 14 can be used as each detection unit of a detection head of a device that simultaneously detects a plurality of detection spots, for example.
  • each imaging circuit 520 of the imaging module 501 shown in FIG. 14 can also be used for performing parallel detection by branching light from one detection spot substantially uniformly.
  • the dynamic range of the image pickup becomes eight times.
  • the maximum number of photons that can be detected simultaneously is 131072 (128 ⁇ 128 ⁇ 8), and linear gradation output of 14 bits to 15 bits can be obtained without performing count correction using the Poisson distribution. .
  • FIG. 15 is a conceptual diagram illustrating an example of a detection head (detection head 502) to which the imaging module 501 according to the third embodiment of the present technology is applied.
  • the detection head 502 includes a condenser lens 102, a pinhole 103, a light homogenizer 560, an optical fiber 570, a light homogenizer 530, an imaging circuit 520, and an image sensor 500. Since the detection head 502 is a modification of the detection head 101 shown in FIG. 2, the same components are denoted by the same reference numerals and description thereof is omitted here. In FIG. 15, the package of the imaging module 501 is not illustrated, and the light uniformizing unit 530, the imaging circuit 520, and the imaging element 500 are illustrated as the imaging module 501.
  • the detection head 502 is provided with a first-stage light uniformizing unit (light uniformizing unit 560) where light from the detection spot 109 passes through the pinhole 103.
  • a plurality of optical fibers are connected to the output side of the light homogenizer 560.
  • the optical fiber 570 is connected to each of a plurality of light uniformizing units 560 provided in the imaging circuit 520.
  • the light homogenizer 560 makes the distribution of incident light (photon count target light) substantially uniform, similar to the light homogenizer 200 shown in FIG.
  • the light homogenizer 560 supplies substantially uniform light to each of the plurality of optical fibers 570 connected thereto. That is, the same number of photons are supplied to the plurality of optical fibers 570, respectively.
  • the light uniformizing unit 560 is an example of a dividing unit described in the claims.
  • the optical fiber 570 is for irradiating the imaging circuit 520 on the imaging device 500 with the light uniformized by the light uniformizing unit 560.
  • the optical fiber 570 is for irradiating the imaging circuit 520 on the imaging device 500 with the light uniformized by the light uniformizing unit 560.
  • the branched lights guided by the optical fiber 570 are substantially uniformed by the second-stage light homogenizer (light homogenizer 530), respectively, and irradiated to the corresponding imaging circuits 520, respectively.
  • the optical fiber 570 has a function of homogenizing light, it is possible to omit the light homogenizer (the light homogenizer 530) disposed in the vicinity of the imaging circuit 520.
  • the plurality of imaging circuits 520 of the detection head 502 are driven in parallel at the same time because the power supply and the synchronization signal are shared.
  • the data processing unit 120 performs mask processing, addition, and count correction described in the first and second embodiments of the present technology for each of the eight imaging circuits 520. To be done. Then, the count values of the eight imaging circuits 520 are added and summed, and the count value of incident light from the detection spot is calculated.
  • a plurality of imaging circuits can be provided on one imaging element (single semiconductor imaging chip).
  • FIG. 16 is a conceptual diagram illustrating an example of classification of image pickup circuits (image pickup elements 500) into four groups of the image pickup element (image pickup element 500) according to the fourth embodiment of the present technology.
  • the image sensor 500 is the same as that shown in FIG. In FIG. 16, four groups of the imaging circuit (imaging circuit 520) are assigned with codes (A, B, C, D) indicating the groups in the light uniformizing unit 530 provided in the imaging circuit 520. And show.
  • the eight image pickup circuits 520 are equally classified into a total of four groups (A, B, C, and D). That is, in the fourth embodiment of the present technology, two imaging circuits form one group, and the imaging circuit 520 is driven for each group.
  • FIG. 17 is a diagram schematically illustrating an example of an exposure operation and a read operation for each group of the imaging circuits 520 classified into four groups in the fourth embodiment of the present technology.
  • the signal readout timing in the explanation of FIG. 17 is referred to as the “n” -th readout timing, and the timing of reading out the previous signal is referred to as the “n ⁇ 1” -th readout timing. .
  • FIG. 17a the exposure operation and the readout operation of the imaging circuit 520 of the A group are shown with the horizontal direction as the direction indicating the time axis and the vertical direction as the direction indicating the row from which the signal is read (read row address).
  • FIG. 17A the “n ⁇ 1” -th read timing (read timing (n ⁇ 1) 621) and the “n” -th read timing (read timing (n) 622) of the imaging circuit 520 of the A group are shown.
  • FIG. 17a shows a reference exposure period (unit exposure period (reference) 624) that is neither shortened nor extended as described in FIG.
  • FIG. 17a shows a reset timing 623, which is a timing for resetting the photodiode and removing electrons accumulated in the photodiode.
  • FIG. 17b shows the exposure operation and readout operation of the image pickup circuit 520 of the B group in the same manner as FIG. 17a.
  • FIG. 17c shows the exposure operation and readout operation of the C group imaging circuit 520
  • FIG. 17b shows the exposure operation and readout operation of the D group imaging circuit 520. Note that the timings and periods shown in b to d of FIG. 17 correspond to those shown in FIG.
  • the imaging circuit 520 sets the reset timing 623 so that a period that is 1 ⁇ 4 of the length of the unit exposure period (reference) 624 becomes the exposure period, and resets the accumulation of electrons in the photodiode at this timing. That is, the accumulation of electrons in the photodiode is reset at a timing (reset timing 623) about 3/4 of the length of the unit exposure period (reference) 624 from the read timing (n-1) 621.
  • Electrons are accumulated in a period from the reset timing 623 to the readout timing (n) 622 (a quarter of the length of the unit exposure period (reference) 624), and accumulated at the readout timing (n) 622. Read out as a signal. In this manner, the imaging circuit 520 is driven so as to receive photons in an exposure period that is 1 ⁇ 4 of the reference unit exposure period.
  • the differences between the exposure operation and readout operation groups will be described.
  • the imaging circuit 520 of the A group the imaging circuits 520 of the B group to the D group are driven so that the photons accumulated in the exposure period 1 ⁇ 4 of the reference unit exposure period become an accumulation signal.
  • the timing of a quarter exposure period (referred to as a group exposure period) for receiving a photon serving as an accumulation signal differs for each group.
  • the imaging circuit 520 of the B group is driven so as to be the reset timing 633 at the same timing as the readout timing (n) 622 of the A group.
  • the read timing (n) 632 is a timing at which about 1 ⁇ 4 of the length of the unit exposure period has elapsed since the reset timing 633.
  • the imaging circuit 520 of the C group has a reset timing 643 at the same timing as the readout timing (n) 632 of the B group, and the readout timing (n is about a quarter of the unit exposure period from this timing. 642.
  • the image pickup circuit 520 of the D group has a reset timing 653 at the same timing as the C group read timing (n) 642, and the read timing (n ) 652.
  • the eight image pickup circuits 520 are driven so that the exposure periods do not overlap between the groups. This eliminates the period in which no photons are detected even though the accumulated signal is generated while accumulating photons for a time shorter than the length of the unit exposure period.
  • FIG. 18 showing a diagram in which exposure periods of four groups are arranged on the time axis.
  • FIG. 18 is a diagram schematically illustrating an example of the effect of performing the photon counting by classifying the imaging circuits 520 into four groups according to the fourth embodiment of the present technology.
  • FIG. 18 shows a diagram in which the exposure periods of the four groups (A, B, C, and D) shown in FIGS. 17A to 17D are arranged on the same time axis.
  • the exposure period of the four groups is an exposure period obtained by dividing a reference exposure period (unit exposure period (reference) 661) that is neither shortened nor extended into four equal parts.
  • the count number of photon counting is explained. Since the eight image pickup circuits 520 of the image pickup device 500 are classified into four groups as shown in FIG. 16, there are two image pickup circuits 520 belonging to one group. Therefore, when the count unit 130 calculates the number of counts in the exposure period of each group, the count unit 130 calculates the sum of the count values of the imaging circuits 520 belonging to the group, the number of imaging circuits 520 belonging to the group, and the imaging circuit 520. The number of counts is calculated with correction based on the ratio to the total number of.
  • the eight image pickup circuits 520 are divided into four groups by dividing the eight image pickup circuits 520 into four groups, the total number of the count values of the two image pickup circuits 520 belonging to the same group is quadrupled so that the count number in the exposure period Can be calculated.
  • the count number in the exposure period of the A group is calculated by multiplying the sum of the count values of the two imaging circuits 520 of the A group by four.
  • the count number in the exposure period of the B group is calculated by multiplying the sum of the two imaging circuits 520 of the B group by four.
  • this correction ensures that light is equalized in the first-stage light homogenizer (light homogenizer 560 in FIG. 15) and that approximately eight photon quantities are incident on the eight imaging circuits. Therefore, it can be performed with high accuracy.
  • the time resolution can be improved by classifying the eight imaging circuits into a plurality of groups and performing different driving for each group. That is, according to the fourth embodiment of the present technology, the accuracy of photon counting can be improved.
  • the photodetectors (imaging devices) according to the first to fourth embodiments of the present technology can be widely applied to conventional electronic devices provided with a photomultiplier tube, an avalanche photodiode, or a photodiode. it can.
  • the present invention can be applied to a fluorescence scanner for an imaging plate and a scintillation counter for radiation.
  • the present invention can also be applied to DNA chip detectors, X-ray imaging devices called DR (Digital Radiography), CT (Computed Tomography) devices, SPECT (Single Photon Emission Tomography) devices, and the like.
  • DR Digital Radiography
  • CT Computed Tomography
  • SPECT Single Photon Emission Tomography
  • FIG. 19 is a schematic diagram illustrating an example of a fluorescence scanner that detects fluorescence of a plurality of spots in parallel by applying the embodiment of the present technology.
  • FIG. 19 shows an inspection table 711, an inspection material 712, four detection modules 720, an excitation light source 713, and a data processing unit 120.
  • FIG. 19 is described assuming a fluorescent scanner in which the inspection material 712 is an imaging plate. That is, the fluorescent scanner shown in FIG. 19 is an example provided with a plurality of detection modules 720 in order to detect photostimulated luminescence from the imaging plate at high speed.
  • the detection module 720 includes an objective lens 721, an excitation light irradiation unit 722, a beam splitter 723, and a detection head 101.
  • excitation light is irradiated from the excitation light irradiation unit 722.
  • the excitation light passes through the beam splitter 723 and is incident on the objective lens 721, and is focused (condensed) in a spot shape by the objective lens 721 and irradiated onto the inspection material 712.
  • the position (focus position) where the excitation light strikes in the state of being most focused on the inspection material 712 is the detection spot shown in the first to fourth embodiments of the present technology.
  • the excitation light generates fluorescence according to the amount of the X-ray latent image.
  • the fluorescence incident on the objective lens 721 is reflected by the beam splitter 723, and then the optical path is guided so as to enter the detection head 101. Then, the detection head 101 performs photon counting of the incident fluorescence.
  • the fluorescence scanner shown in FIG. 19 four detection modules 720 are arranged, and excitation light is simultaneously irradiated to four detection spots, and fluorescence detection is performed in parallel.
  • the inspection table 711 is moved by one spot by the stepping motor, and the next detection is performed.
  • the example which supplies excitation light to the excitation light irradiation part 722 of each detection module from the same light source (excitation light source 713) was shown in FIG. 19, in addition, the light source which generates excitation light for every detection module (for example, an example in which an LED (Light Emitting Diode) is installed is also conceivable.
  • the band filter in the middle of the optical path is omitted, but the accuracy of detection is improved by setting various band filters at appropriate positions. For example, by providing a filter that limits the band of excitation light at the excitation light exit of the excitation light source 713, the probability that only target fluorescence is generated is improved.
  • a background noise can be reduced by providing a filter that transmits only the fluorescence wavelength.
  • the embodiment of the present technology is applied to a fluorescent scanner, a plurality of detection heads can be easily provided. This is because the place (image sensor 110) for detecting the light of the detection head is a CMOS image sensor, so that it can be mass-produced at a low price. That is, if the embodiment of the present technology is applied to a fluorescent scanner, the detection speed can be improved as compared with the use of an expensive photomultiplier tube.
  • FIG. 20 is a schematic diagram showing an example different from FIG. 19 of the fluorescence scanner that detects the fluorescence of a plurality of spots in parallel by applying the embodiment of the present technology.
  • FIG. 20 shows an example of a fluorescent scanner that performs line scanning by applying the embodiment of the present technology.
  • the fluorescent scanner of FIG. 20 includes an inspection table 751, an inspection material 752, and a microlens array 753.
  • the fluorescent scanner includes an excitation light irradiation unit 754, an optical fiber 755, a light uniformizing unit 761, an image sensor 762, and a data processing unit 120.
  • FIG. 20a description will be made assuming a YZ axis in which the vertical direction is the Y axis and the horizontal direction is the Z axis.
  • FIG. 20b shows a diagram focusing on the microlens array 753 and the excitation light irradiation unit 754, assuming an XZ axis where the vertical direction is the X axis and the horizontal direction is the Z axis.
  • the microlenses are arranged in a line in a line (one line in the Y-axis direction of a in FIG. 20a).
  • an excitation light irradiation unit 754 is provided in parallel with the microlenses arranged in a line.
  • the excitation light irradiating unit 754 irradiates the individual light condensing positions (detection spots) of the plurality of microlenses arranged in a line of the microlens array 753 in a lump.
  • the relationship between one microlens in the microlens array 753 and the excitation light from the excitation light irradiation unit 754 is shown in FIG. 20b assuming the XZ axis.
  • the excitation light is collectively irradiated.
  • the fluorescence generated from each detection spot (corresponding to a detection pixel) is collected by the microlens of the microlens array 753.
  • the condensed fluorescence is incident on the optical fibers 755 corresponding to the respective microlenses, and the optical fibers 755 are guided to the corresponding light uniformizing units 761.
  • the light is uniformed by the light uniformizing unit 761 and the pixel array unit of the corresponding image sensor 762 is irradiated substantially uniformly.
  • the optical fiber 755 when the optical fiber 755 is an optical fiber having a light uniformizing function, the optical fiber 755 has the function of the light uniformizing unit 761.
  • the light uniformizing unit 761 can be omitted.
  • a fluorescent scanner capable of performing line scanning can be manufactured at a low price, and the detection speed can be improved.
  • FIG. 21 is a schematic diagram showing an example in which the embodiment of the present technology is applied to an X-ray scintillation detector.
  • FIG. 21 shows a scintillator 732, an optical fiber 733, a light uniformizing unit 741, and an image sensor 742.
  • X-rays X-rays 731
  • An optical fiber 733 (or a light guide) is connected to the scintillator 732 for each detection unit (detection pixel unit in the case of conventional photodiode detection).
  • the photons incident on each detection unit are guided to the optical fiber 733 and reach the light uniformizing unit 741, are substantially uniformed, and are radiated substantially uniformly onto the pixel array unit of the image sensor 742.
  • the optical fiber 733 is an optical fiber having a light uniformizing function
  • the optical fiber 733 has a function of the light uniformizing unit 741.
  • the light uniformizing unit 741 can be omitted.
  • the embodiment of the present technology can be applied to a scintillation detector.
  • a scintillation detector For example, if such a configuration is introduced into a detector of a CT apparatus, it becomes possible to detect scintillation light with a much higher sensitivity than a detector using a conventional photodiode or the like. It can contribute to low exposure. Furthermore, since a large-scale external device including an AD converter is not required, the device can be reduced in size and cost.
  • a similar configuration can be introduced for detection of gamma rays, such as SPECT and PET, which conventionally used a photomultiplier tube.
  • FIGS. 19 to 21 the example of the four imaging elements has been described.
  • the imaging module (imaging module 501) according to the third embodiment of the present technology, the size and weight can be further reduced. Furthermore, the price can be reduced.
  • the detection head in the applied electronic device for example, a fluorescence detection device
  • the detection head in the applied electronic device for example, a fluorescence detection device
  • the influence of noise on the signal can be reduced.
  • the light detection unit image pickup device
  • the light detection unit image pickup device
  • it can be manufactured extremely inexpensively. That is, high parallelization of hundreds or thousands can be easily realized. For this reason, for example, in the case of a fluorescent scanner, it is possible to secure high throughput by increasing the parallelism while reducing the detection spot size and increasing the resolution.
  • the effect is not limited only to an electronic device provided with a large number of detection heads, but the same effect can be obtained in an electronic device using a single detection head.
  • a pocket dosimeter having a small size and a light weight and an ultra-high sensitivity can be realized using an inexpensive semiconductor imaging device.
  • the accuracy of photon counting can be improved by making the light uniformized by the light uniformizing unit incident on the image sensor.
  • the embodiment of the present technology has been described assuming fluorescence detection, but the present technology is not limited to fluorescence, and the embodiment of the present technology can be applied to various apparatuses that require measurement of weak light. .
  • photon counting according to embodiments of the present technology is very effective, and high-precision photon counting can be performed inexpensively and easily.
  • man-machine interface and diabetes diagnosis by measuring the amount of reflected light by irradiating blood vessels with near-infrared light in a specific band and detecting differences in light absorption due to hemoglobin and blood sugar. Is underway.
  • the application of the present technology is also effective as a photodetector in such a field.
  • the processing procedure described in the above embodiment may be regarded as a method having a series of these procedures, and a program for causing a computer to execute these series of procedures or a recording medium storing the program. You may catch it.
  • this recording medium for example, a hard disk, CD (Compact Disc), MD (MiniDisc), DVD (Digital Versatile Disc), memory card, Blu-ray Disc (Blu-ray Disc (registered trademark)) or the like can be used.
  • this technique can also take the following structures. (1) Distribution of light incident on an image pickup device in which a plurality of pixels are arranged and whose number of photons is to be detected in a direction orthogonal to the optical axis is made substantially uniform, and the uniformized light An image pickup apparatus including a light uniformizing unit that supplies the image pickup element to the image pickup element. (2) The image pickup device performs digital determination on the number of incident photons by the supplied uniformized light to each of the plurality of pixels, and outputs a determination result value of the digital determination for each of the plurality of pixels.
  • the calculation unit uses difference correction information indicating a relationship between the number of photons actually incident on the plurality of pixels and the total value, and calculates the number of photons of the incident light based on the total value.
  • the imaging device according to (2) which is calculated.
  • the image sensor performs binary determination as the digital determination,
  • the calculation unit excludes the determination result value of the pixel having a large dark current based on pixel position information for identifying a pixel having a large dark current among the plurality of pixels, and calculates the total value.
  • the imaging device any one of (2) to (4), wherein: (6) The imaging device according to (5), wherein the calculation unit corrects the total value based on a ratio between a number of pixels from which the determination result value is excluded and a total number of the plurality of pixels.
  • the image sensor performs binary determination as the digital determination, The imaging device according to (6), wherein the calculation unit calculates the number of photons of the incident light based on the corrected total value using difference information related to a Poisson distribution or a relationship approximated to a Poisson distribution.
  • the imaging device includes a plurality of pixel arrays each driven independently, The imaging apparatus according to any one of (1) to (7), wherein the light uniformizing unit is provided in pairs for each of the plurality of pixel arrays. (9) It further comprises a dividing unit that substantially uniforms the distribution of the incident light in the orthogonal direction of the optical axis and divides the uniformed incident light into a plurality of incident lights. The imaging apparatus according to (8), wherein the light uniformizing unit supplies the plurality of incident light beams to the pair of pixel arrays.
  • the plurality of pixel arrays have the same exposure period length and start timing; Each of the plurality of pixel arrays performs digital determination on the number of incident photons by the supplied light to each of the plurality of pixels in the pixel array, and outputs a determination result value of the digital determination for each of the plurality of pixels.
  • the calculation unit further includes a calculation unit that sums the output determination result values of the plurality of pixels for each exposure period, and calculates the number of photons of the incident light in the exposure period based on the summed total value.
  • the plurality of pixel arrays are classified into a plurality of groups having different exposure period start timings, Each of the plurality of pixel arrays performs digital determination on the number of incident photons by the supplied light to each of the plurality of pixels in the pixel array, and outputs a determination result value of the digital determination for each of the plurality of pixels. Summing up the output determination result values of each of the plurality of pixels in the group unit, and based on a ratio between the number of pixel arrays belonging to the group related to the summed sum value and the total number of the plurality of pixel arrays.
  • the imaging apparatus further including a calculation unit that corrects the total value and calculates the number of photons of the incident light during the exposure period of the group based on the corrected total value.
  • Distribution of the incident light which is a target for detecting the number of photons on an image sensor in which a plurality of pixels are arranged, and which is the target for detecting the number of photons, in a direction orthogonal to the optical axis is made substantially uniform.
  • a light homogenizer for supplying the homogenized light;
  • An image sensor that performs digital determination for each of a plurality of pixels with respect to the number of incident photons by the supplied light, and outputs a determination result value of the digital determination for each of the plurality of pixels;
  • a calculation unit that sums the output determination result values of the plurality of pixels in units of frames and calculates the number of photons of the incident light during the exposure period of the frame based on the summed total value.
  • a light homogenizer that substantially uniformizes the distribution of incident light, which is a detection target of the number of photons, in a direction orthogonal to the optical axis, and supplies the uniformed light; and incident photons by the supplied light
  • a photostimulated luminescence detection scanner including a detection unit including a plurality of imaging units each including a plurality of imaging units that perform digital determination for each of a plurality of pixels and output a determination result value of the digital determination for each of the plurality of pixels.
  • the incident light that is the detection target of the number of photons to the image sensor in which a plurality of pixels are arranged and the distribution of the incident light that is the detection target of the number of photons in the direction orthogonal to the optical axis is made substantially uniform.
  • An imaging method comprising: calculating a sum of determination result values of each of the plurality of pixels in units of frames, and calculating the number of photons of the incident light during the exposure period of the frame based on the summed total value.

Abstract

La présente invention entend améliorer la précision de comptage des photons dans un dispositif de capture d'image. Un dispositif de capture d'image est doté d'une unité de formation de lumière uniforme. L'unité de formation de lumière uniforme prévue dans ce dispositif de capture d'image traite la lumière incidente qui entre dans un élément de capture d'image du dispositif de capture d'image, une pluralité de pixels étant disposés à l'intérieur, de manière à former une répartition sensiblement uniforme des photons dans une direction qui coupe à angle droit l'axe optique de la lumière incidente dans laquelle le nombre de photons est détecté. L'unité de formation de lumière uniforme fournit de la lumière uniforme à l'élément de capture d'image du dispositif de capture d'image dans lequel est disposée la pluralité de pixels.
PCT/JP2012/081257 2011-12-09 2012-12-03 Dispositif de capture d'image, appareil électronique, scanner de détection de luminescence stimulée de manière optique et procédé de capture d'image WO2013084839A1 (fr)

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EP12854949.0A EP2790400A1 (fr) 2011-12-09 2012-12-03 Dispositif de capture d'image, appareil électronique, scanner de détection de luminescence stimulée de manière optique et procédé de capture d'image
CN201280059247.XA CN103975580B (zh) 2011-12-09 2012-12-03 成像设备、电子装置、光激励发光检测扫描器和成像方法
US14/362,313 US9462190B2 (en) 2011-12-09 2012-12-03 Imaging apparatus, an electronic device, and imaging method to uniformize distribution of incident light, and a photostimulated luminescence detection scanner
US15/249,654 US10063784B2 (en) 2011-12-09 2016-08-29 Imaging apparatus, an electronic device, and imaging method to uniformize distribution of incident light, and a photostimulated luminescence detection scanner

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JP2011-270240 2011-12-09

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US15/249,654 Continuation US10063784B2 (en) 2011-12-09 2016-08-29 Imaging apparatus, an electronic device, and imaging method to uniformize distribution of incident light, and a photostimulated luminescence detection scanner

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US20160366322A1 (en) 2016-12-15
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